APOD: Northern Winter Night (2020 Dec 25)

Comments and questions about the APOD on the main view screen.
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APOD Robot
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APOD: Northern Winter Night (2020 Dec 25)

Post by APOD Robot » Fri Dec 25, 2020 5:06 am

Image Northern Winter Night

Explanation: Orion always seems to come up sideways on northern winter evenings. Those familiar stars of the constellation of the Hunter are caught above the trees in this colorful night skyscape. Not a star at all but still visible to eye, the Great Nebula of Orion shines below the Hunter's belt stars. The camera's exposure reveals the stellar nursery's faint pinkish glow. Betelgeuse, giant star at Orion's shoulder, has the color of warm and cozy terrestrial lighting, but so does another familiar stellar giant, Aldebaran. Alpha star of the constellation Taurus the Bull, Aldebaran anchors the recognizable V-shape traced by the Hyades Cluster toward the top of the starry frame.

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Sa Ji Tario

Re: APOD: Northern Winter Night (2020 Dec 25)

Post by Sa Ji Tario » Fri Dec 25, 2020 5:46 am

I hope you are having a good night and I wish you Merry Christmas!

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Ann
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Re: APOD: Northern Winter Night (2020 Dec 25)

Post by Ann » Fri Dec 25, 2020 9:19 am

What a stunningly beautiful image. Do follow the link, The camera's exposure, to see the incredibly star-studded sky of the full resolution image.
APOD Robot wrote:

The camera's exposure reveals the stellar nursery's faint pinkish glow. Betelgeuse, giant star at Orion's shoulder, has the color of warm and cozy terrestrial lighting, but so does another familiar stellar giant, Aldebaran.

Indeed, the Orion Nebula is pinkish, although that is a color that we have no hope of seeing with our eyes in any cosmic nebula. And Betelgeuse and Aldebaran both stand out because of their yellow-orange color.

m7MSxo3EKgdcC8tjT8n7EHY2[1].jpeg
Orion constellation with long curving Barnard's Loop at left,
and round Lambda Orionis Nebula at top. Photo: Angel G. Fuentes.
But there are two more colors that should be pointed out in the image.

Two faint red emission nebulas are visible in the APOD as well as in the image I have posted here at top. It's the long curving Barnard's Loop encircling much of the lower part of the Orion constellation, and the round Lambda Orionis Nebula at top.

The Lambda Orionis Nebula is ionized by hot, O8-type star Lambda Orionis, and Barnard's Loop may either be a supernova remnant, or else it might be ionized by the collective ultraviolet radiation of the hot stars in and near the Orion Nebula and Orion's Belt. It is interesting to see how much brighter, but also how much smaller, the Orion Nebula is compared with Barnard's Loop and the Lambda Orionis Nebula.


The second image I have posted, the one of the central Milky Way, brings out the rarity of blue stars in our galaxy. A few prominent blue stars are visible in it, particularly Lambda, Nu and Kappa Scorpii (at lower left), and the pink Lagoon Nebula, itself ionized by hot blue stars, stands out at upper right. The two red (and dust-reddened) nebulas near Kappa and Nu Scorpii are the Cat's Foot Nebula and the Lobster Nebula.

But what dominates the scene is a diffuse yellowish glow, emitted by hundreds of millions of mostly faint yellow and red stars.

Most stars in the Milky Way are faint and yellowish. We can see with our eyes that bright yellow-orange stars like Betelgeuse and Aldebaran are unusual.

But stars like Alnitak, Alnilam and Mintaka are unusual too, and not only for the beautiful line they create in the sky as they make up Orion's Belt (at least from our point of view), and for their very high luminosities. They are unusual for their bluish color too, and for their hot temperatures that create their color.

Hot bright blue stars are rare! Give them their due!

Ann
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Last edited by Ann on Fri Dec 25, 2020 3:07 pm, edited 1 time in total.
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Chris Peterson
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Re: APOD: Northern Winter Night (2020 Dec 25)

Post by Chris Peterson » Fri Dec 25, 2020 2:12 pm

I was driving back last night from a day of high country snowshoeing, heading south in the absolute darkness of central Colorado, watching Orion sitting just above the horizon in front of us (and Jupiter and Saturn setting over the Sawatch range to our right). Truly a marker of the middle of winter.
Chris

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Re: APOD: Northern Winter Night (2020 Dec 25)

Post by orin stepanek » Fri Dec 25, 2020 3:32 pm

I wanted a background of this!

WinterSceneBlock.jpg

So I cheated! :mrgreen:

WinterSceneBlock.jpg

Not as good as the original; but still nice!
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Re: APOD: Northern Winter Night (2020 Dec 25)

Post by Chris Peterson » Fri Dec 25, 2020 3:58 pm

orin stepanek wrote:
Fri Dec 25, 2020 3:32 pm
I wanted a background of this!

So I cheated! :mrgreen:
Not as good as the original; but still nice!
Really? You put Orion on The Rack? Isn't that a human rights violation?
Chris

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Re: APOD: Northern Winter Night (2020 Dec 25)

Post by orin stepanek » Fri Dec 25, 2020 4:03 pm

Chris Peterson wrote:
Fri Dec 25, 2020 3:58 pm
orin stepanek wrote:
Fri Dec 25, 2020 3:32 pm
I wanted a background of this!

So I cheated! :mrgreen:
Not as good as the original; but still nice!
Really? You put Orion on The Rack? Isn't that a human rights violation?

Sorry; I did stretch him a bit! He's a little taller now!
Britannia picture1
Man-rack-illustration-The-National-and-Domestic.jpg
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Orin

Smile today; tomorrow's another day!

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And leave not a rack behind.

Post by neufer » Fri Dec 25, 2020 8:34 pm

Click to play embedded YouTube video.
Chris Peterson wrote:
Fri Dec 25, 2020 3:58 pm
orin stepanek wrote:
Fri Dec 25, 2020 3:32 pm

I wanted a background of this! So I cheated! :mrgreen:
Not as good as the original; but still nice!
Really? You put Orion on The Rack? Isn't that a human rights violation?
http://www.sirbacon.org/gallery/west.htm
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Re: APOD: Northern Winter Night (2020 Dec 25)

Post by alcor » Sat Dec 26, 2020 1:51 am

Merry Christmas
or should I say
Happy Season
to Adam Block
Arne